The 30 Nato allies are set to sign off on the accession protocols for Sweden and Finland, sending the membership bids of the two nations to the alliance capitals for legislative approvals.
The move will further increase Russia’s strategic isolation in the wake of its invasion of neighbouring Ukraine in February and military struggles there since.
The 30 ambassadors and permanent representatives are to formally approve the decisions of last week’s Nato summit, when the alliance made the historic decision to invite Russia’s neighbour Finland and Scandinavian partner Sweden to join the military club.
Despite the agreement in the alliance, parliamentary approval in member state Turkey could still pose problems for their final inclusion as members.
Last week, Turkish leader Recep Tayyip Erdogan warned that Ankara could still block the process if the two countries fail to fully meet Turkey’s demand to extradite terror suspects with links to outlawed Kurdish groups or the network of an exiled cleric accused of a failed 2016 coup in Turkey.
He said Turkey’s Parliament could refuse to ratify the deal.
It is a potent threat since Nato accession must be formally approved by all 30 member states, which gives each a blocking right.
Tuesday’s expected signing-off does bring both nations deeper into Nato’s fold already.
As close partners, they have already attended some meetings that involved issues that immediately affected them.
As official invitees, they can attend all meetings of the ambassadors even if they do not yet have any voting rights.